【英文标准名称】:StandardTestMethodforAirborneAsbestosConcentrationinAmbientandIndoorAtmospheresasDeterminedbyTransmissionElectronMicroscopyDirectTransfer(TEM)
【原文标准名称】:用透射式电子显微镜直接转移法测定周围环境和室内空气中气载石棉浓度的标准试验方法
【标准号】:ASTMD6281-2009
【标准状态】:现行
【国别】:美国
【发布日期】:2009
【实施或试行日期】:
【发布单位】:美国材料与试验协会(US-ASTM)
【起草单位】:D22.07
【标准类型】:(TestMethod)
【标准水平】:()
【中文主题词】:
【英文主题词】:air;ambientair;amphibole;asbestos;chrysotile;electronmicroscopy;indooratmospheres;microscopy;Poissonfrequencydistribution;Transmissionelectronmicroscopy(TEM);AirborneasbestosbydirecttransferTEM;Ambientair/atmosphericanaly
【摘要】:Thistestmethodisapplicabletothemeasurementofairborneasbestosinawiderangeofambientairsituationsandfordetailedevaluationofanyatmosphereinwhichasbestosstructuresarelikelytobepresent.Mostfibersinambientatmospheresarenotasbestos,andtherefore,thereisarequirementforfiberstobeidentified.Mostoftheairborneasbestosfibersinambientatmosphereshavediametersbelowtheresolutionlimitofthelightmicroscope.Thistestmethodisbasedontransmissionelectronmicroscopy,whichhasadequateresolutiontoallowdetectionofsmallthinfibersandiscurrentlytheonlytechniquecapableofunequivocalidentificationofthemajorityofindividualfibersofasbestos.Asbestosisoftenfound,notassinglefibers,butasverycomplex,aggregatedstructures,whichmayormaynotalsobeaggregatedwithotherparticles.Thefibersfoundsuspendedinanambientatmospherecanoftenbeidentifiedunequivocallyifsufficientmeasurementeffortisexpended.However,ifeachfiberweretobeidentifiedinthisway,theanalysiswouldbecomeprohibitivelyexpensive.Becauseofinstrumentaldeficienciesorbecauseofthenatureoftheparticulatematter,somefiberscannotbepositivelyidentifiedasasbestoseventhoughthemeasurementsallindicatethattheycouldbeasbestos.Therefore,subjectivefactorscontributetothismeasurement,andconsequently,averyprecisedefinitionoftheprocedureforidentificationandenumerationofasbestosfibersisrequired.Themethoddefinedinthistestmethodisdesignedtoprovideadescriptionofthenature,numericalconcentration,andsizesofasbestos-containingparticlesfoundinanairsample.Thetestmethodisnecessarilycomplexbecausethestructuresobservedarefrequentlyverycomplex.Themethodofdatarecordingspecifiedinthetestmethodisdesignedtoallowreevaluationofthestructure-countingdataasnewapplicationsformeasurementsaredeveloped.Allofthefeasiblespecimenpreparationtechniquesresultinsomemodificationoftheairborneparticulatematter.Eventhecollectionofparticlesfromathree-dimensionalairbornedispersionontoatwo-dimensionalfiltersurfacecanbeconsideredamodificationoftheparticulatematter,andsomeoftheparticles,inmostsamples,aremodifiedbythespecimenpreparationprocedures.However,theproceduresspecifiedinthistestmethodaredesignedtominimizethedisturbanceofthecollectedparticulatematerial.Thistestmethodappliestoanalysisofasinglefilteranddescribestheprecisionattributabletomeasurementsforasinglefilter(see13.1).Multipleairsamplesareusuallynecessarytocharacterizeairborneasbestosconcentrationsacrosstimeandspace.Thenumberofsamplesnecessaryforthispurposeisproportionaltothevariationinmeasurementacrosssamples,whichmaybegreaterthanthevariationinameasurementforasinglesample.1.1Thistestmethodisananalyticalprocedureusingtransmissionelectronmicroscopy(TEM)forthedeterminationoftheconcentrationofasbestosstructuresinambientatmospheresandincludesmeasurementofthedimensionofstructuresandoftheasbestosfibersfoundinthestructuresfromwhichaspectratiosarecalculated.1.1.1Thistestmethodallowsdeterminationofthetype(s)ofasbestosfiberspresent.1.1.2Thistestmethodcannotalwaysdiscriminatebetweenindividualfibersoftheasbestosandnon-asbestosanaloguesofthesameamphibolemineral.1.2Thistestmethodissuitablefordeterminationofasbestosinbothambient(outdoor)andbuildingatmospheres.1.2.1Thistestmethodisdefinedforpolycarbonatecapillary-porefiltersorcelluloseester(eithermixedestersofcelluloseorcellulosenitrate)filtersthroughwhichaknownvolumeofairhasbeendrawnandforblankfilters.Product Code:SAE AMS4773
Title:Silver Alloy, Brazing Filler Metal, 60Ag - 30Cu - 10Sn, 1115 to 1325 掳F (602 to 718 掳C) Solidus-Liquidus Range
Issuing Committee:Ams D Nonferrous Alloys Committee
Scope:This specification covers a silver alloy in the form of wire, rod, sheet, strip, foil, pig, powder, shot, and chips and a viscous mixture (paste) of powder in a suitable binder.